Sliding plug for a molten metal container

ABSTRACT

A plug device for a container for molten metals having a refractory movable closure which can open and close a flow path, and which in its open position permits flow of metal into a chamber which is normally of greater cross-section that that of the flow path.

United States Patent Seybold Apr. 15, 1975 SLIDING PLUG FOR A MOLTENMETAL [56] References Cited CONTAINER UNITED STATES PATENTS [75]inventor: Rolf Seybold, Solingen, Germany 2,863,189 12/1958 Beck 222/559UX 3,354,939 11/1967 Caldern 222/559 UX [73] Ass'gneei Evert! Germany3,574,341 12/1968 Fehling et a]. 2 222/559 ux [22] Filed: Oct. 17, 1973Primary ExaminerRobert B. Reeves [211 App! 407381 AssistantExaminerDavid A. Scherbel [30] Foreign Application Priority Data 57ABSTRACT Germany 2251484 A plug device for a container for molten metalshaving a refractory movable closure which can open and [52] US. Cl i,222/559; 25l/l44 Close a fl path, d which in its open position pen [5 lIlit. Cl BZZCI 37/00 mits fl of metal i 3 Chamber which i normally f[58] new of Search 222/559 greater cross-section that that of the flowpath.

222/DIG. 13, 461; 25l/l44; 164/335 10 Claims, 3 Drawing Figures r i K/'SLlDING PLUG FOR A MOLTEN METAL CONTAINER The invention relates to asliding plug for casting ladles or for similar vessels. from whichmolten metals. particularly steel. are discharged through a bottomoritice. comprising a guide which is fitted on the base of the ladlefrom the outside. and a refractory sliding part which is capable ofmoving relative to the guide between a position closing the bottomorifice and one which opens it.

Sliding plugs of this kind are frequently used instead of other closingdevices. which consist essentiaily of a stopper rod which is introducedfrom above into the molten metal. and closes or opens the bottomorifice. Unfortunately this known arrangement presents substantialproblems which are mainly due to the fact that the stopper rod cannot beoperated reliably enough at the very high temperature of the liquidmetal. How

ever. on the other hand. casting by means of a stopper rod hasadvantages. amongst which in particular. control of the flow rate byvarying adjustment. is worthy of mention, which is not normally possiblewith the conventional sliding plug. Sliding plugs can normally only beoperated so as to be fully open or closed; in any intermediate position.the opening edge of the sliding plug would be subjected to excessivewear. and finally lead to scaling difficulties A further disadvantage ofthe conventional sliding plug is that very large mechan ical forces areneeded for its operation. over a relatively long distance of travel.Along this travel. the refractory lining of the sliding plug is alsosubjected to considerable wear. The fact that the sliding plug can onlybe operated into its fully open position. causes the molten metal to bedischarged at a very high speed. particularly at the start of thecasting process. due to the substantial static pressure. which candamage moulds by erosion and the like.

On this basis. the objective ofthe invention is the design of a slidingplug of the type described above. such that on the one hand it has theadvantages of the controllability of a plug operated with a stopper rod.and on the other hand. it has the accessibility of a sliding plug whichis operable from the outside. In accordance with the invention. this isachieved in that the sliding part is connected to the refractory sealingcone or a corresponding sealing body. particularly of rotationallysymmetrical shape. and that it is movable in a vertical direction. wherethe sealing cone in the lowered closing position. abuts with itsperipheral surface on a compltr mentary surface or matching edge. and inits raised opening position. permits the flow of metal into a clos ingchamber formed by the guide or sliding part. the cross-section of thisclosing chamber normally being greater than the flow cross-sectionadjustable by the seal. and from which the metal is discharged through abottom orifice.

A sliding plug designed in this manner has the advantage that it can becontrolled within wide limits. for which purpose its sliding part ismoved vertically. Dur ing this. the bottom orifice is not subjected tothe full static pressure of the molten metal in the casting ladle orsimilar vessel. but only to the static pressure of the metal in theclosing chamber. The closing chamber drains completely after closureofthe bottom orifice. as sufficient space can be left for air to enter.between the said chamber and the guide. In this area. an annular gap isproduced. which has the additional advantage that if the sealing coneshould be damaged and allow too much molten metal to be discharged. thismolten metal would solidify in the annular gap. and block the hole. Forthe controllability it is particularly advantageous that not only is ashort adjusting path sufficient. but that for this purpose. only verylow mechanical forces are needed. A further element of safety isachieved in that if the actuating device fails. automatic closing takesplace. as the sealing cone then drops down. and its wall acts as a seal.This behaviour of the sealing cone can also be utilised as a rapidshut-off. where some kind of component is built in. which can bewithdrawn. so that the entire assembly drops. down. and brings thesealing cone into its sealing position.

The complementary surface of the bottom orifice matching the peripheralsurface ofthe sealing cone. advantageously has the shape of an annularblock. which is inserted into the bottom orifice which corresponds toits dimensions. and is held in place by a plate supporting it. fixed onthe bottom of the ladle.

The invention provides design forms which differ from one anotherdepending on whether the closing chamber is made from the guide or thesliding part. In the event ofthe closing chamber being formed from thesliding part. an open pipe section which extends downwards from thebottom the ladle acts as a guide. in which the sliding part whichcontains the closing chamber. is adjustable with lateral play. Thelateral play here produces the annular gap through which the air cancnter. Naturally. a protective gas can also be fed in at this point.

In the alternative case of the closing chamber being formed from theguide. the said guide is conveniently made up or a refractory-linedcylinder containing the closing chamber. where this cylinder is linkedwith the base of the ladle and is completely enclosed with the exceptionof the bottom outlet andof an inner pipe sleeve extending verticallyupwards. The sliding part is here capable of sliding with lateral playwithin the pipe sleeve. and is designed as a block carrying the sealingcone. and covering the pipe sleeve with an annular collar. Both the pipesleeve and the collar are provided with an outer or inner flange suchthat both flanges. in an upper limiting position of the sealing cone.are in sealing contact with one another i.e.. create a seal.

in all cases. the sliding part is provided with a supporting memberextending along the axis ofthe bottom orifice. the said extension makingvertical movement of the sliding part possible.

The high accuracy of dosing which can be achieved with the new slidingplug. allows the sliding part to be included as a controlling member ina control circuit. In particular. the sliding part can be supported by aspring which is adjustable to different forces, such that the springtries to press the sliding part upwards. but is prevented from doing soby the higher or lower level to which the closing chamber is filled. sothat a state of equilibrium results, depending on the adjustment of thespring. Hence the flow rate can easily be maintained at a predetermined.adjust-able nominal value For further illustration of the invention. werefer to drawings of design examples. In these:

FIG. 1 shows a cross-section of the new sliding plug.

FIG. 2 shows an elevation. partially in section. corresponding to FIG.i. and

FIG. 3 shows a cross-section through a modified design form of theinvention.

FIG. I shows first of all a partial illustration of the bottom.marked 1. of a casting ladle or similar vessel. The vessel has beenlined in the conventional manner. with refractory brickwork. The bottomorifice 2 can be seen. the surround 3 of which. is made of refractorybrickwork with a particularly high degree of resistance. Followingcompletion of the ladle bottom. sealing cone 5 and annular block 4 wereinserted from underneath. and plate 6. together with the pipe section 7serving as guide. were screwed on in such a manner that plate 6 holdsannular block 4 in position. The sealing cone 5 is designed with ananchoring facility 8. the upper end of which. as can he seen from FIG.I. expands. while the lower end is threaded.

The sliding part 9. with closing chamber 10. is movable inside pipesleeve 7. The closing chamber has an annular shape. and is arranged inthe refractory in sert ll of sliding part 9. The lower section ofanchoring 8 passes through sliding part 9. and is held on the base ofthe sliding part by means of nut 12. In this manner the sealing cone 5is linked with sliding part 9.

ln addition. bottom orifice [3 can be seen. again made from a specialrefractory insert 14. which expands conically upwards. and is insertedinto the conical mantle tube 15. The annular gap between pipe section 7and sliding part 9 makes possible not only completely unimpeded verticalmovement of the sliding part. but also permits the entry of air. so thatthe closing chamber 10 can be drained completely. In addition. in theevent ofdamage to the sealing cone 5. the molten metal can solidify inthe said annular gap. so that the sliding part 9 is then blocked. andall the molten metal can be discharged correctly through the bottomorifice 13. A cam l6 presses against the end of the anchoring 8. thiscam being located on the actuating shaft 17. which itself can beactuated with the aid of the handwheel 18. as can be seen from FIG. 2.FIG. 2 in addition. illustrates lateral telescopic guides l9 and 20. Thesliding part 9 can also be moved by other actuators. such as forexample. hydraulic. pneumatic or electromechanical drives. This isparticularly relevant if the sliding part 9 is to be designed ascontrolling element in a control circuit. or is to be controlled inrelation to. for instance. the level of molten metal in the castingladle or in a mould.

FIG. 3 again illustrates the sealing cone 5 inserted in an annular block4. Here. the sliding part is designed as block 24 which carries thesealing cone 5. and has an annular collar 26. To the ladle bottom. acylinder 21 is connected. which is closed save for bottom orifice [3 atthe base. and for an inner pipe sleeve 25 extending upwards. Thiscylinder 21 forms the closing chamber 10. which is also ringshaped. Atthe same time. the pipe section 25 forms the guide for the sliding part.The latter can be pressurised at its lower end by means which are notshown in this illustraton. in such a manner that adjustment of height ispossible. by which the sealing cone 5 is either raised or lowered. andthus allows the desired quantity of molten metal to be discharged intothe closing chamber 10. from which it is discharged through bottomoutlet 13. Pipe section 25 can have an additional upper outer flange 22.while col lar 26 of the sliding part can have a lower inner llange 23.so that the two flanges come into sealing contact with one another whenthe sealing cone 5 is in the upper limiting position. Here we are againdealing with a sea] as in the design form according to FIGS. l and 2.which also becomes effective when sealing cone 5 fails. In this event.the sliding part which is made of refractory material. is forced upwardsby the buoyancy forces. so that the closing chamber fills up completely.without the metal being able to flow out of any opening other than thebottom orifice 13.

The feature present in all design forms of the invention. by which theclosing chamber has a cross-section which is normally greater than theflow cross-section which is adjustable with the sealing cone. is to beinterpreted such that it may even be possible in exceptional cases. tocreate a flow cross-section which can exceed that of the closingchamber. by means of operating the sliding part into the extremeposition.

In the design form in accordance with FIG. 2. additional telescopicguides 19 and 20 have been illustrated. Additional guides of this oranother design. allow the movement of the sliding part in all designforms of the invention. to be so precise that a uniform annular gap isleft free in relation to the other guide.

What l claim is:

l. A plug for a casting ladle having a surface defining a bottomorifice. said plug comprising a guide which is mounted on the exteriorof the base of the ladle. a refractory part which is movably mounted onthe ladle for movement relative to the guide between a first positionclosing said bottom orifice and a second position opening said bottomorifice. a refractory sealing body. said refractory part being connectedto said refractory sealing body and being movable in a substantiallyverti cal direction. said sealing body being arranged so that in thefirst closing position its peripheral surface sealingly engages saidsurface on the ladle defining said bottom orifice and in the secondopening position it permits the flow of metal through said bottomorifice. and a closing chamber formed in said plug. the crosssection ofsaid closing chamber being greater than the cross-section of said bottomorifice. said closing chamber having an exit orifice in the bottomportion thereof which is laterally offset from said bottom orifice.

2. A sliding plug in accordance with claim I. wherein the ladle surfacewhich is complementary to the peripheral surface ofthe sealing body isdefined by an annular block which is mounted on the bottom of the ladle.and a supporting plate fixed on the ladle bottom for supporting saidannular block.

3. A sliding plug in accordance with claim 1. wherein the guide is anopen pipe section extending downwardly from the ladle bottom. and therefractory part contains the closing chamber and is movable within saidguide. said part being spaced from said guide to provide a small gaptherebetween so that said closing chamber is in communication with thesurrounding atmosphere through said gap.

4. A sliding plug in accordance with claim 3., wherein an additionalguide is provided to enable movement of the refractory part withoutsubstantial variation of said gap.

5. A sliding plug in accordance with claim I. wherein the guide is arefractory-lined housing containing the closing chamber and exitorifice. said housing being connected to the base of the ladle andhaving an inner open pipe sleeve extending vertically upwardly therein.said housing being completely enclosed with the excep tion of said exitorifice and said inner pipe sleeve. and

5 wherein said sliding part is a refractory block having its lowerportion movably disposed within the pipe sleeve. said block carrying thesealing body and having an annular collar enclosing the upper portion ofthe pipe sleeve.

6. A sliding plug in accordance with claim 5. wherein said pipe sectionhas an upper outer flange and said collar has a lower inner flange suchthat both of said flanges, in an upper limiting position of the sealingbody. are in sealing contact with one another.

7. A sliding plug according to claim 5 wherein the lower portion of saidblock is spaced from said pipe sleeve to provide a small gaplherebetween so that the closing chamber is in communication with thesurrounding atmosphere through said gap.

8. A sliding plug in accordance with claim I, wherein the refractorypart has a supporting member extending along the axis of the bottomorifice. by means of which substantially vertical movement of the partis made possible.

9. A sliding plug according to claim I wherein the refractory sealingbody is of rotationally symmetrical shape.

10. A sliding plug according to claim 9. wherein the refractory sealingbody has a frustoconical portion.

1. A plug for a casting ladle having a surface defining a bottomorifice, said plug comprising a guide which is mounted on the exteriorof the base of the ladle, a refractory part which is movably mounted onthe ladle for movement relative to the guide between a first positionclosing said bottom orifice and a second position opening said bottomorifice, a refractory sealing body, said refractory part being connectedto said refractory sealing body and being movable in a substantiallyvertical direction, said sealing body being arranged so that in thefirst closing position its peripheral surface sealingly engages saidsurface on the ladle defining said bottom orifice and in the secondopening position it permits the flow of metal through said bottomorifice, and a closing chamber formed in said plug, the crosssection ofsaid closing chamber being greater than the crosssection of said bottomorifice, said closing chamber having an exit orifice in the bottomportion thereof which is laterally offset from said bottom orifice.
 2. Asliding plug in accordance with claim 1, wherein the ladle surface whichis complementary to the peripheral surface of the sealing body isdefined by an annular block which is mounted on the bottom of the ladle,and a supporting plate fixed on the ladle bottom for supporting saidannular block.
 3. A sliding plug in accordance with claim 1, wherein theguide is an open pipe section extending downwardly from the ladlebottom, and the refractory part contains the closing chamber and ismovable within said guide, said part being spaced from said guide toprovide a small gap therebetween so that said closing chamber is incommunication with the surrounding atmosphere through said gap.
 4. Asliding plug in accordance with claim 3, wherein an additional guide isprovided to enable movement of the refractory part without substantialvariation of said gap.
 5. A sliding plug in accordance with claim 1,wherein the guide is a refractory-lined housing containing the closingchamber and exit orifice, said housing being connected to the base ofthe ladle and having an inner open pipe sleeve extending verticallyupwardly therein, said housing being completely enclosed with theexception of said exit orifice and said inner pipe sleeve, and whereinsaid sliding part is a refractory block having its lower portion movablydisposed within the pipe sleeve, said block carrying the sealing bodyand having an annular collar enclosing the upper portion of the pipesleeve.
 6. A sliding plug in accordance with claim 5, wherein said pipesection has an upper outer flange and said collar has a lower innerflange such that both of said flanges, in an upper limiting position ofthe sealing body, are in sealing contact with one another.
 7. A slidingplug according to claim 5 wherein the lower portion of said block isspaced from said pipe sleeve to provide a small gap therebetween so thatthe closing chamber is in communication with the surrounding atmospherethrough said gap.
 8. A sliding plug in accordance with claim 1, whereinthe refractory part has a supporting member extending along the axis ofthe bottom orifice, by means of which substantially vertical movement ofthe part is made possible.
 9. A sliding plug according to claim 1wherein the refractory sealing body is of rotationally symmetricalshape.
 10. A sliding plug according to claim 9, wherein the refractorysealing body has a frustoconical portion.